A known door opening and closing apparatus for a vehicle is disclosed in JP5-78862U as first and second embodiments thereof. According to the known door opening and closing apparatus for the vehicle according to the first embodiment of JP5-78862U, a striker is provided at a hinge arm (i.e., a bracket) fixedly mounted to a slide door, and a hook for engaging with the striker is provided on a body. According to the door opening and closing apparatus for the vehicle, when the slide door is fully open, the striker and the hook engage with each other for restricting the slide door from moving. A support lever rotatably supported by the hinge arm pulls the striker upward and thereby releases the engagement of the striker with the hook, and thus the restriction on the movement of the slide door is released.
According to a known door opening and closing apparatus for a vehicle according to the second embodiment of JP5-78862U, a striker is provided at a body, and a latch and a pawl are provided on a hinge arm (a bracket) fixedly mounted to a slide door. According to the known door opening and closing apparatus for the vehicle, when the slide door is fully open, the striker and the latch engage with each other and the pawl restricts the latch from rotating, thereby restricting the slide door from moving. The pawl is pulled upward to release the engagement of the striker with the latch to release the restriction on the movement of the slide door.
While the hinge arm (the bracket) is fixedly mounted to the vehicle door related to the known door opening and closing apparatus for the vehicle, a hinge arm of a door opening and closing apparatus having a four-link hinge is movable. Therefore, common application of the mechanical structure used in the known art into the door opening and closing apparatus having the four-link hinge causes following inconveniences. That is, a cable, which is used for an unlocking mechanism for releasing retention (i.e., holding) of the slide door, needs to be arranged along the four-link hinge arm. Then, the cable arrangement needs to have allowance for play of the cable, which produces wider variance in a length of the cable. Depending on the wire length, the stroke of the wire may be insufficient to release the retention of the door even when the cable is pulled. Further, a bending radius of the cable becomes smaller, where a higher sliding resistance is generated between the wire and a pipe enclosing the wire, and thus a higher force is required to release the retention of the slide door. Furthermore, a longer cable causes cost increase.
A need thus exists for a door opening and closing apparatus for a vehicle, which is not susceptible to the drawback mentioned above.